Handling a Query Zero Results

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Let me preface with I have used Apex only a little bit.

I have a visual force page that will be hosted on sites publicly. I take the value of the url string and then query a custom field on the account object to return a few variables to display. The query works and returns what I need however if I get 0 results I get an error, I would expect that. I have been trying to use .size() to catch if no results but can’t seem to get the syntax right. See Code below for 1 variation.

Any help and explanation would be much appreciated. Thanks!

public class application {

private final Account account;

/** This will return the original URL **/
public String currentURL { get {return site.getOriginalUrl(); } }

/** Remove any slashes **/
public String accountURL { get; set; } {
    if(currentURL.contains('/')) accountURL = currentURL.replace('/','');
    else accountURL = currentURL;
}

public application() {
   account = [SELECT Id, Name, LogoID__c FROM Account WHERE URL_Code__c = :accountURL LIMIT 1];  
   if (account.size() == 0) {
       return null;
   } else {
       return account.get(0); 
   }

}

public Account getAccount() {
    return account;
}

}

This is the code that worked in case others come across this.

public class application {

private final Account account;

/** This will return the origina; URL **/
public String currentURL { get {return site.getOriginalUrl(); } }

/** Remove any slashes **/
public String accountURL { get; set; } {
    if(currentURL.contains('/')) accountURL = currentURL.replace('/','');
    else accountURL = currentURL;
}

public application() {
   List<Account> accs = [SELECT Id, Name, LogoID__c FROM Account WHERE URL_Code__c = :accountURL LIMIT 1];
   if(accs != null && accs.size() > 0) {
        account = accs[0];
   } else {     
       account = null;
   }
 }

public Account getAccount() {
    return account;
}
}

Answer

The exception is thrown because you are assigning the results of your query directly to an account, rather than a list of accounts. When you assign the results of a query directly to an instance of a variable Salesforce will throw an exception if the query returns zero rows.

As you are using an instance of an account rather than a list you cannot use the size method to test for a valid result.

Personally in this situation I would like to see null assigned to your account variable but that’s not how the platform works.

There are a couple of ways of working around this issue. The first is to use a try/catch to handle the flow around this. Whilst often seen on the platform it is generally considered bad practice to use exception handling to manage logic flow – in this case you are expecting the possibility that you won’t return any values so this doesn’t count as an exception. Anyway for completeness you will often see this;

try{
    account = [SELECT Id, Name, LogoID__c FROM Account WHERE URL_Code__c = :accountURL LIMIT 1];
} catch(Exception ex){
    account = null;
}

A better way to perform this is to assign the results of the query to a list, test the size of the list and react as necessary. Like so:

Account acct = null;
List<Account> accs = [SELECT Id, Name, LogoID__c FROM Account WHERE URL_Code__c = :accountURL LIMIT 1];
if(!accs.isEmpty()){
    acct = accs[0];
}

Attribution
Source : Link , Question Author : Brian , Answer Author : Community

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